Re: diffrnece b/w Te-metric & LSP metric

LSP is built from one or more Link's(each link have his own TE metric)
so naturally TE metric will come first.

I will try to demonstrate the diff with an Example:

lest say you have the following topology:

          +---------+ +----------+ +--------+ +----------+
          | R1 +-------+ R2 +------+ R3 +-----+ R6 |
          +-------+-+ +----+-----+ +----+---+ +----+-----+
                  | | | |
                  | | | |
                  | +---+-----+ +----+---+ |
                  +----------+ R4 +------> R5 +----------+
                             +---------+ +--------+

Each connection between each router have its own TE metric lets say
they are all 10

Now you create 2 LSP's to the same destination

1. R1 -- R2 -- R3 -- R6
2. R1 -- R4 -- R5 -- R3 -- R6

So the first LSP Calculated Metric will be 30 and the second will be
40, and now you wish to make the second LSP better or you want to make
it equal for load sharing, you can by modifying the LSP metric

hope that this make it better :-)

Regards,

On Fri, Feb 8, 2013 at 6:07 PM, shekhar sharma
<shekhar.sharma21_at_gmail.com> wrote:
>
> thks shiran... ,,, i hve earlier gone thorugh tht link shared by you.... :)
>
> My confusion is " In the process of LSP formation , what is the step by step process ,,, first te-metric comes into picture or LSP metric"
> and " diffrence b/w the two is not yet cleared 2 me "
>
> thanks,
> Shekhar
>
> On Fri, Feb 8, 2013 at 8:47 PM, shiran guez <shiranp3_at_gmail.com> wrote:
>>
>> te metric is done under the IGP (ISIS or OSPF) see below example default metric is 10 when I have modified te metric on one of the interfaces (under the ISIS):
>>
>> lab_at_j1# set protocols isis interface em0.21 level 2 te-metric 222
>>
>> See that under the link below the IGP metric remain 10 and the TE metric was modified to 222
>>
>> lab_at_j1> show isis database level 2 extensive
>> IS-IS level 2 link-state database:
>>
>> j1.00-00 Sequence: 0xe1a, Checksum: 0xcd59, Lifetime: 1143 secs
>> IS neighbor: j1.02 Metric: 10
>> Two-way fragment: j1.02-00, Two-way first fragment: j1.02-00
>> IS neighbor: j2.02 Metric: 10
>> Two-way fragment: j2.02-00, Two-way first fragment: j2.02-00
>> IS neighbor: j4.02 Metric: 10
>> Two-way fragment: j4.02-00, Two-way first fragment: j4.02-00
>> IP prefix: 11.21.0.0/24 Metric: 10 Internal Up
>> IP prefix: 11.41.0.0/24 Metric: 10 Internal Up
>> IP prefix: 11.61.0.0/24 Metric: 10 Internal Up
>> IP prefix: 149.1.1.1/32 Metric: 0 Internal Up
>> V6 prefix: 2001:11:21::/64 Metric: 10 Internal Up
>> V6 prefix: 2001:11:41::/64 Metric: 10 Internal Up
>> V6 prefix: 2001:11:61::/64 Metric: 10 Internal Up
>> V6 prefix: 2001:149:1::1/128 Metric: 0 Internal Up
>>
>> Header: LSP ID: j1.00-00, Length: 400 bytes
>> Allocated length: 1492 bytes, Router ID: 149.1.1.1
>> Remaining lifetime: 1143 secs, Level: 2, Interface: 0
>> Estimated free bytes: 935, Actual free bytes: 1092
>> Aging timer expires in: 1143 secs
>> Protocols: IP, IPv6
>>
>> Packet: LSP ID: j1.00-00, Length: 400 bytes, Lifetime : 1198 secs
>> Checksum: 0xcd59, Sequence: 0xe1a, Attributes: 0x3 <L1 L2>
>> NLPID: 0x83, Fixed length: 27 bytes, Version: 1, Sysid length: 0 bytes
>> Packet type: 20, Packet version: 1, Max area: 0
>>
>> TLVs:
>> Area address: 49.0001 (3)
>> Speaks: IP
>> Speaks: IPV6
>> IP router id: 149.1.1.1
>> IP address: 149.1.1.1
>> Hostname: j1
>> IS extended neighbor: j2.02, Metric: default 10
>> IP address: 11.21.0.1
>> Local interface index: 65, Remote interface index: 0
>> Traffic engineering metric: 222
>> Current reservable bandwidth:
>> Priority 0 : 590Mbps
>> Priority 1 : 590Mbps
>> Priority 2 : 570Mbps
>> Priority 3 : 570Mbps
>> Priority 4 : 570Mbps
>> Priority 5 : 570Mbps
>> Priority 6 : 570Mbps
>> Priority 7 : 570Mbps
>> Maximum reservable bandwidth: 1000Mbps
>> Maximum bandwidth: 1000Mbps
>> Administrative groups: 0 <none>
>> ...
>>
>>
>> Now for the LSP there is a very good explanation in juniper doc (something rare :-))
>>
>> http://www.juniper.net/techpubs/en_US/junos11.1/topics/usage-guidelines/mpls-configuring-lsp-metrics.html
>>
>> in short the LSP is a path created from 1 or more links and you may reuse that path to reach a destination, in case you have multiple LSP's that can reach the same destination I you wish to make one of them preferred.
>>
>>
>> Hope that helps with your confusion.
>>
>>
>> On Fri, Feb 8, 2013 at 3:07 PM, shekhar sharma <shekhar.sharma21_at_gmail.com> wrote:
>>>
>>> Correct Brian.
>>>
>>> Thanks for your input...
>>>
>>> But I am working in junos environment only,,,and In junos Te-metric & LSP
>>> metric are two different things.
>>>
>>> My understanding is that,, we will configure te-metric lower then the IGP
>>> cost on every router and configure the IGP metric at the higest value.
>>> This is done so that traffic should always take MPLS path rather than IGP
>>> path.
>>>
>>> Second parameter is LSP metric ,,,which can be configured mannualy or
>>> dynamic inherted from IGP. best practice is to static configure LSP metric
>>> on each router if you are using RSVP full mesh.This is required to have
>>> stablity inn the n/w ,,change in IGP will not affect LSP,,,as LSP metric is
>>> staticaly configured.
>>>
>>> But I am still confused on how these parameters came into picture in LSP
>>> formation.
>>>
>>>
>>>
>>> On Fri, Feb 8, 2013 at 5:37 AM, Brian McGahan <bmcgahan_at_ine.com> wrote:
>>>
>>> > What Cisco calls the TE metric is what I believe Juniper calls the LSP
>>> > metric. The key is that there is an IGP metric for the link and a
>>> > separately configurable TE metric. If you want to change the TE tunnel's
>>> > cost but not affect IGP you have that option. Normally the TE metric is
>>> > inherited from the IGP metric, but you can manually change it with the
>>> > "mpls traffic-eng administrative-weight" command.
>>> >
>>> > See the following:
>>> >
>>> > http://www.cisco.com/en/US/docs/ios/mpls/configuration/guide/mp_te_cfg_path_calc.html
>>> >
>>> >
>>> > http://www.cisco.com/en/US/docs/ios-xml/ios/mpls/command/mp-m4.html#GUID-61EE6705-8B24-44B4-BDA4-720C362F71CF
>>> >
>>> >
>>> > HTH,
>>> >
>>> > Brian McGahan, CCIE #8593 (R&S/SP/Security)
>>> > bmcgahan_at_INE.com
>>> >
>>> > Internetwork Expert, Inc.
>>> > http://www.INE.com
>>> >
>>> > -----Original Message-----
>>> > From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
>>> > shekhar sharma
>>> > Sent: Thursday, February 07, 2013 1:36 PM
>>> > To: Cisco certification
>>> > Subject: diffrnece b/w Te-metric & LSP metric
>>> >
>>> > Hi All,
>>> >
>>> >
>>> > I have been working on MPLS traffic engineering and concepts like
>>> > forwarding adjaency these days.
>>> >
>>> > I am confused on the diffrence b/w Te-metric & LSP metric and
>>> > how,when,where to manipulate them.
>>> >
>>> > If anyone can share some docs or links that will be helpful.or if can
>>> > explain to me
>>> >
>>> > thanks,
>>> > Shekhar
>>> >
>>> >
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>>>
>>
>>
>>
>> --
>> Shiran Guez
>> MCSE CCNP NCE1 JNCIA-ENT JNCIS-ENT JNCIP-ENT CCIE #20572
>> http://cciep3.blogspot.com
>> http://www.linkedin.com/in/cciep3
>> http://twitter.com/cciep3
>
>

--
Shiran Guez
MCSE CCNP NCE1 JNCIA-ENT JNCIS-ENT JNCIP-ENT CCIE #20572
http://cciep3.blogspot.com
http://www.linkedin.com/in/cciep3
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